
DocID024597 Rev 5
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RM0351
Flexible static memory controller (FSMC)
471
16.5.1
External memory interface signals
and
list the signals that are typically used to interface with NOR
Flash memory, SRAM and PSRAM.
Note:
The prefix “N” identifies the signals which are active low.
NOR Flash memory, non-multiplexed I/Os
The maximum capacity is 512 Mbits (26 address lines).
Table 66. Programmable NOR/PSRAM access parameters
Parameter Function Access
mode
Unit
Min.
Max.
Address
setup
Duration of the address
setup phase
Asynchronous
AHB clock cycle
(HCLK)
0
15
Address hold
Duration of the address hold
phase
Asynchronous,
muxed I/Os
AHB clock cycle
(HCLK)
1
15
Data setup
Duration of the data setup
phase
Asynchronous
AHB clock cycle
(HCLK)
1
256
Bust turn
Duration of the bus
turnaround phase
Asynchronous and
synchronous read
/ write
AHB clock cycle
(HCLK)
0
15
Clock divide
ratio
Number of AHB clock cycles
(HCLK) to build one memory
clock cycle (CLK)
Synchronous
AHB clock cycle
(HCLK)
2
16
Data latency
Number of clock cycles to
issue to the memory before
the first data of the burst
Synchronous
Memory clock
cycle (CLK)
2
17
Table 67. Non-multiplexed I/O NOR Flash memory
FMC signal name
I/O
Function
CLK
O
Clock (for synchronous access)
A[25:0] O Address
bus
D[15:0]
I/O
Bidirectional data bus
NE[x]
O
Chip Select, x = 1..4
NOE
O Output
enable
NWE
O Write
enable
NL(=NADV)
O
Latch enable (this signal is called address
valid, NADV, by some NOR Flash devices)
NWAIT
I
NOR Flash wait input signal to the FMC